The present invention relates to an arrangement for fastening a circular saw blade to a trunnion of reduced diameter projecting from one end of a drive shaft and comprising two annular clamping elements arranged on the trunnion at opposite sides of the saw blade and frictionally holding the latter between the two clamping elements, one of which abuts on a shoulder formed at the junction of the drive shaft and the trunnion whereas the other clamping element abuts directly or under interposition of a pressure ring against the head of a screw screwed into a threaded bore extending from the end face of the trunnion into the latter. In a known arrangement of this kind in which the friction between the clamping element and the saw blade serves as a slip clutch preventing overloading of the saw blade, there is usually provided on the saw blade a symbol in the form of an arrow indicating the direction of rotation of the drive shaft which should prevent wrong mounting of the saw blade on the latter respectively on the trunnion projecting therefrom. Despite this indication on the saw blade, it happens quite often that the saw blade is mounted on the trunnion in a wrong manner because no constructive means are provided which would prevent actually a wrong mounting of the saw blade on the trunnion. At an arrangement in which the saw blade is fixedly coupled to the trunnion, it is already known to construct the coupling means assymmetrically so that the saw blade may be mounted on the trunnion only in the correct position (Deutsches Gebrauchsmuster No. 18 78 647). This solution is, however, not possible in a fastening arrangement with a slip clutch between the saw blade and the trunnion since in such an arrangement a permanent fixed connection between the saw blade and trunnion is not usable.